The invention relates to a closure for hermetically sealing, while nevertheless allowing easy reopening, a bottle or a similar container having a neck with a discharge orifice, a neck end surface surrounding the orifice, and below the neck end surface a mouth lip in the form of an annular bead with a constriction at its lower side, the said closure comprising a cap as the sealing head with a roof wall and cap side walls extending around the roof wall, with a slitting for the purpose of spreading when the cap is set on the bottle mouth which slitting extends from the lower mouth rim transversely to it, and with an inside annular bead on the cap side wall projecting inward for the purpose of gripping the lower side of the mouth lip of the bottle when in the closed position, further a sealing element for sealing the discharge orifice of the bottle when in closed position, further a finger-actuated lift element on the actuation side of the cap, and further a fastening device spanning in annular manner each of the slits present in the cap side wall when in the closed position by hermetically pressing the inside annular bead of the cap side wall of the bottle against the constricted lower side of the lip of the bottle mouth, the said fastening device comprising at least one tensioning (or "clamping") means which in the closed position of the bottle is tensioned by stresses tangential to the cap side wall, and thereby prevents the spreading of each slit present in the side wall, and an omnidirectional uniform pressing of the annular inside bead against the lower side of the lip of the bottle neck moutn.
Such a closure means already is known from Swiss Pat. No. 605 306 of REFIL Aktiengesellschaft at Triesenberg, Duchy of Liechtenstein and from their German Offenlegungsschrift No. 2 554 887.
Now it was found with respect to that closure means that when it is manufactured by the injection molding method, the material will concentrate more on the production tool than was the case originally for prototype production. This makes the overall closure means stiffer, the bridging members in the form of straps bridging the slits are less elastic, the closure means must be emplaced with higher compression in the filling process, and most of all, greater effort is required when first opening the bottle, or another container, when lifting the pull-off nose (lifting element), and again replacing it is that much more difficult.
On the other hand, this substantially more rigid closure means is not substantially more resistant to internal pressure than one made from a less dense material which is correspondingly more elastic.
In order to pasteurize the bottle contents, the temperature must be raised at least to 62.degree. C. for at least 20 minutes; the closure means to-date however withstands only a temperature of 56.degree. C. Accordingly it must be made of a still harder material. If the closure means hower shall withstand these pasteurizing conditions, it will be even more difficult to put it on and take it off a bottle mouth.